From: <noreply@so...>  20021222 01:21:32

Bugs item #657382, was opened at 20021221 20:20 You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=657382&group_id=4933 Category: None Group: None Status: Open Resolution: None >Priority: 4 Submitted By: Stavros Macrakis (macrakis) Assigned to: Nobody/Anonymous (nobody) Summary: defint/limit infinite loop Initial Comment: integrate(1/(x^51),x,1,inf) appears to get into an infinite loop inside $limit (over 4 hours CPU).  >Comment By: Stavros Macrakis (macrakis) Date: 20021221 20:21 Message: Logged In: YES user_id=588346 Sorry,. I forgot to mention that this is under 5.5 GCL/Windows 2000.  You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=657382&group_id=4933 
From: <noreply@so...>  20021222 01:20:50

Bugs item #657382, was opened at 20021221 20:20 You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=657382&group_id=4933 Category: None Group: None Status: Open Resolution: None Priority: 5 Submitted By: Stavros Macrakis (macrakis) Assigned to: Nobody/Anonymous (nobody) Summary: defint/limit infinite loop Initial Comment: integrate(1/(x^51),x,1,inf) appears to get into an infinite loop inside $limit (over 4 hours CPU).  You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=657382&group_id=4933 
From: <noreply@so...>  20021222 01:21:32

Bugs item #657382, was opened at 20021221 20:20 You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=657382&group_id=4933 Category: None Group: None Status: Open Resolution: None >Priority: 4 Submitted By: Stavros Macrakis (macrakis) Assigned to: Nobody/Anonymous (nobody) Summary: defint/limit infinite loop Initial Comment: integrate(1/(x^51),x,1,inf) appears to get into an infinite loop inside $limit (over 4 hours CPU).  >Comment By: Stavros Macrakis (macrakis) Date: 20021221 20:21 Message: Logged In: YES user_id=588346 Sorry,. I forgot to mention that this is under 5.5 GCL/Windows 2000.  You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=657382&group_id=4933 
From: SourceForge.net <noreply@so...>  20060409 20:40:41

Bugs item #657382, was opened at 20021221 18:20 Message generated for change (Settings changed) made by robert_dodier You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=657382&group_id=4933 Please note that this message will contain a full copy of the comment thread, including the initial issue submission, for this request, not just the latest update. >Category: Lisp Core  Integration Group: None Status: Open Resolution: None Priority: 4 Submitted By: Stavros Macrakis (macrakis) Assigned to: Nobody/Anonymous (nobody) Summary: defint/limit infinite loop Initial Comment: integrate(1/(x^51),x,1,inf) appears to get into an infinite loop inside $limit (over 4 hours CPU).  Comment By: Stavros Macrakis (macrakis) Date: 20021221 18:21 Message: Logged In: YES user_id=588346 Sorry,. I forgot to mention that this is under 5.5 GCL/Windows 2000.  You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=657382&group_id=4933 
From: SourceForge.net <noreply@so...>  20070613 18:31:02

Bugs item #657382, was opened at 20021221 20:20 Message generated for change (Comment added) made by rtoy You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=657382&group_id=4933 Please note that this message will contain a full copy of the comment thread, including the initial issue submission, for this request, not just the latest update. Category: Lisp Core  Integration Group: None Status: Open Resolution: None Priority: 4 Private: No Submitted By: Stavros Macrakis (macrakis) Assigned to: Nobody/Anonymous (nobody) Summary: defint/limit infinite loop Initial Comment: integrate(1/(x^51),x,1,inf) appears to get into an infinite loop inside $limit (over 4 hours CPU).  >Comment By: Raymond Toy (rtoy) Date: 20070613 14:31 Message: Logged In: YES user_id=28849 Originator: NO FWIW, this still happens in 5.12 cvs. What's happening is that maxima has computed the antiderivative correctly and is now trying to carefully substitute in the limits of integration to make sure everything is on the right sheet. This is basically done in takeprincipal and intsubs. I don't understand why maxima does the limit essentially twice like limit(anti,x,1+eps,plus)  limit(anti,x,1eps,minus). This seems to be where maxima is getting stuck. If it were to finish, maxima would then go and take the limit as eps goes to zero from above. Perhaps if the pole is at one of the limits of integration as it is here, maxima should do something else? I think the current code assumes the pole is within the integration interval.  Comment By: Stavros Macrakis (macrakis) Date: 20021221 20:21 Message: Logged In: YES user_id=588346 Sorry,. I forgot to mention that this is under 5.5 GCL/Windows 2000.  You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=657382&group_id=4933 
From: SourceForge.net <noreply@so...>  20070619 17:28:11

Bugs item #657382, was opened at 20021221 20:20 Message generated for change (Comment added) made by rtoy You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=657382&group_id=4933 Please note that this message will contain a full copy of the comment thread, including the initial issue submission, for this request, not just the latest update. Category: Lisp Core  Integration Group: None Status: Open Resolution: None Priority: 4 Private: No Submitted By: Stavros Macrakis (macrakis) Assigned to: Nobody/Anonymous (nobody) Summary: defint/limit infinite loop Initial Comment: integrate(1/(x^51),x,1,inf) appears to get into an infinite loop inside $limit (over 4 hours CPU).  >Comment By: Raymond Toy (rtoy) Date: 20070619 13:27 Message: Logged In: YES user_id=28849 Originator: NO If ININTERVAL in defint.lisp is slightly modified to use ASKGREAT instead of ASKGREATEQ, where ASKGREAT checks if x > y instead of x >= y, then maxima quickly says the integral is divergent. I think this is correct since 1/(x^51) has a partial fraction expansion of 1/5/(x1) + <stuff>. Do not know if this change is the correct change or not.  Comment By: Raymond Toy (rtoy) Date: 20070613 14:31 Message: Logged In: YES user_id=28849 Originator: NO FWIW, this still happens in 5.12 cvs. What's happening is that maxima has computed the antiderivative correctly and is now trying to carefully substitute in the limits of integration to make sure everything is on the right sheet. This is basically done in takeprincipal and intsubs. I don't understand why maxima does the limit essentially twice like limit(anti,x,1+eps,plus)  limit(anti,x,1eps,minus). This seems to be where maxima is getting stuck. If it were to finish, maxima would then go and take the limit as eps goes to zero from above. Perhaps if the pole is at one of the limits of integration as it is here, maxima should do something else? I think the current code assumes the pole is within the integration interval.  Comment By: Stavros Macrakis (macrakis) Date: 20021221 20:21 Message: Logged In: YES user_id=588346 Sorry,. I forgot to mention that this is under 5.5 GCL/Windows 2000.  You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=657382&group_id=4933 
From: SourceForge.net <noreply@so...>  20080217 21:44:16

Bugs item #657382, was opened at 20021221 20:20 Message generated for change (Comment added) made by dgildea You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=657382&group_id=4933 Please note that this message will contain a full copy of the comment thread, including the initial issue submission, for this request, not just the latest update. Category: Lisp Core  Integration Group: None >Status: Closed >Resolution: Fixed Priority: 4 Private: No Submitted By: Stavros Macrakis (macrakis) Assigned to: Nobody/Anonymous (nobody) Summary: defint/limit infinite loop Initial Comment: integrate(1/(x^51),x,1,inf) appears to get into an infinite loop inside $limit (over 4 hours CPU).  >Comment By: Dan Gildea (dgildea) Date: 20080217 16:44 Message: Logged In: YES user_id=1797506 Originator: NO Commented out call to $logcontract from takeprincipal in defint.lisp rev 1.55. $logcontract was causing size of antiderivative to blow up. No ill effects in test suite. (%i12) integrate(1/(x^51),x,1,inf) ; Integral is divergent  an error. To debug this try debugmode(true); (%i13) integrate(1/(x^51),x,0,inf) ; Principal Value (%o13) (2*sqrt(2*sqrt(5)+10)*atan((sqrt(5)3)*sqrt(2*sqrt(5)+10)/(4*sqrt(5))) +2*sqrt(102*sqrt(5))*atan(sqrt(102*sqrt(5))*(sqrt(5)+3)/(4*sqrt(5))) sqrt(2)*sqrt(sqrt(5)+5)*%pisqrt(2)*sqrt(5sqrt(5))*%pi) /20  Comment By: Raymond Toy (rtoy) Date: 20070619 13:27 Message: Logged In: YES user_id=28849 Originator: NO If ININTERVAL in defint.lisp is slightly modified to use ASKGREAT instead of ASKGREATEQ, where ASKGREAT checks if x > y instead of x >= y, then maxima quickly says the integral is divergent. I think this is correct since 1/(x^51) has a partial fraction expansion of 1/5/(x1) + <stuff>. Do not know if this change is the correct change or not.  Comment By: Raymond Toy (rtoy) Date: 20070613 14:31 Message: Logged In: YES user_id=28849 Originator: NO FWIW, this still happens in 5.12 cvs. What's happening is that maxima has computed the antiderivative correctly and is now trying to carefully substitute in the limits of integration to make sure everything is on the right sheet. This is basically done in takeprincipal and intsubs. I don't understand why maxima does the limit essentially twice like limit(anti,x,1+eps,plus)  limit(anti,x,1eps,minus). This seems to be where maxima is getting stuck. If it were to finish, maxima would then go and take the limit as eps goes to zero from above. Perhaps if the pole is at one of the limits of integration as it is here, maxima should do something else? I think the current code assumes the pole is within the integration interval.  Comment By: Stavros Macrakis (macrakis) Date: 20021221 20:21 Message: Logged In: YES user_id=588346 Sorry,. I forgot to mention that this is under 5.5 GCL/Windows 2000.  You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=657382&group_id=4933 